Hopefully in the sense that real girls could modify themselves to be cat girls and fend off (perhaps with claws etc. added through modification) guys who think they're asking for it as if you're talking about the "classic" "anime totally-not-a-slave-or-pet-just-a-"domestic-companion" waifu who you could probably order as a catgirl version of your favorite anime best girl looks-and-personality-wise" archetype you'd need them to somehow be created at 18 (unless you want to give them a childhood just to take it away with "domestic training" brainwashing) in a way that wouldn't make them still too-soon-past-creation to be too young to consent and you'd need to make them stay 18 forever.